[INFO] cloning repository https://github.com/zhang12295/rust_study
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/zhang12295/rust_study" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhang12295%2Frust_study", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhang12295%2Frust_study'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e6463d6098af0de0e8df696789bda370660f435c
[INFO] testing zhang12295/rust_study against master#ebf0cf75d368c035f4c7e7246d203bd469ee4a51 for pr-137940
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhang12295%2Frust_study" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] error: unable to write symref for HEAD: No space left on device


failed to checkout https://github.com/zhang12295/rust_study

Caused by:
    command failed: exit status: 1